Cylinder-head gasket comprising an edge-to-edge stop ring which is connected by means of stapling

ABSTRACT

A cylinder head gasket comprising an edge-to-edge stopper with a stopper/support sheet connection that provides better support for the stopper and does not create excessive stresses.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/FR02/03270, filed Sep. 25, 2002. This application claims the benefitof French Patent Application 01/12492, filed Sep. 28, 2001. Thedisclosures of the above applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a cylinder head gasket comprising anedge-to-edge stopper characterized more particularly by the mode ofconnection of the stopper to the remainder of the gasket.

BACKGROUND OF THE INVENTION

A cylinder head gasket comprises two sheets with at least one openingcorresponding to the opening of a combustion chamber. At least one ofthe two sheets, and preferably both, comprise a rib disposed around eachopening at a distance from the edge of the opening, wherein the ribs aredeformed toward the interior of the gasket.

In addition, the gasket comprises an intermediate support sheetinterposed between the two external sheets and opposite the ribs, aswell as a stopper in the form of an annular lining that has an internaldiameter that approximately corresponds to the diameter of the opening.An external diameter of the stopper is smaller than that of the ribs.The stopper is disposed from edge to edge along the extension of thesupport sheet.

The connection between the stopper and the support sheet is generallyobtained by welding, gluing or the like. French patent applicationFR-00.12669, filed in the name of Applicant, proposes a method ofconnecting the stopper to its support sheet by a radial expansion of thestopper. This method, however, is difficult to implement because itcauses deformation of the entire stopper.

SUMMARY OF THE INVENTION

The present invention proposes a novel cylinder head gasket comprisingan edge-to-edge stopper with a novel stopper/support sheet connectionthat provides better support for the stopper, and does not createexcessive stresses at the level of the latter.

To this end, the present invention provides a cylinder head gasket withat least one opening that corresponds to a combustion chamber. In oneembodiment of the invention, at least one sheet, referred to asexternal, comprises a circular rib that surrounds the opening. The sheetis disposed a distance from the edge of the opening. In anotherembodiment, a support sheet is disposed against the face of the externalsheet that bears the projecting rib. The support sheet comprises anopening with a diameter that is greater than the opening of the externalsheet so as to define a space wherein a stopper is disposed in the formof an annular lining. The stopper has an internal diameter thatcorresponds to the opening and an external diameter that isapproximately adjusted to the opening of the support sheet so as to bedisposed from edge to edge. The connection between the stopper and thesupport sheet comprises at least one projecting part arranged on eitherone of the two elements and is disposed in a hollow cutout that has anapproximately cooperating shape arranged at the level of the otherelement. The projecting part has anti-stripping shapes as well as atleast one plastic deformation close to the projecting part or parts soas to create a slight expansion, ensuring a connection between the twoelements by wedging.

Due to the anti-stripping shapes, wedging stresses only exist locallyand do not bring about excessive deformations of the sheet.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view of a part of the cylinder head gasketin a plane parallel to the sheets, according to a principle of thepresent invention;

FIG. 2 is a cross-sectional view of a part of the cylinder head gasketin a plane parallel to the sheets, according to another principle of thepresent invention;

FIG. 3 is a cross-sectional view of a part of a cylinder head gasket ina plane parallel to the sheets according to yet another principle of thepresent invention;

FIG. 4 is a cross-sectional view of a part of a cylinder head gasket ina plane parallel to the sheets according to a principle of the presentinvention;

FIGS. 5A and 5B are cross-sectional views along two different radii ofthe cylinder head gasket of FIG. 4; and

FIGS. 6A to 6C are top views of different principles of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

The figures show a cylinder head gasket 10 comprising at least oneexternal sheet 12 and preferably two, as illustrated in FIGS. 5A and 5B,with at least one opening 14 that corresponds to a combustion chamber ofan engine block. At least one of the external sheets 12, and preferablyboth, comprises a circular rib 16 that surrounds the opening 14 and isdisposed a distance from the edge of opening 14. The rib or ribs arepreferably deformed toward the interior of the gasket.

In a known manner, the intermediate support sheet 18 is interposedbetween the external sheets 12. In the case where the gasket has onlyone external sheet 12, the support sheet 18 is disposed against the faceof the external sheet 12 bearing the projecting rib 16.

The support sheet comprises an opening that is concentric with theopening 14 of the external sheet or sheets 12, and has a diameter thatis greater than the opening 14 so as to define a space wherein a stopper20 is disposed in the form of an annular lining that has an internaldiameter that corresponds to that of the opening 14, and an externaldiameter that is approximately adjusted to the opening of the supportsheet.

Advantageously, the stopper comprises at least one zone of thickness X1that is greater than a thickness X2 of the support sheet so as toconstitute a limiter against the crushing of the ribs, a first barrierof tightness, and to permit the arching of at least one external sheetso as to limit the deflections of the latter during operation.

Depending on the case, the external diameter of stopper 20 can besmaller than that of ribs 16 so that the support sheet 18 fits betweenthe ribs 16, or it can be greater than that of ribs 16 so that a zone ofthe stopper with a thickness less than X1 fits between ribs 16, asillustrated in FIGS. 5A and 5B.

According to the invention, as illustrated by the drawings, theconnection between stopper 20 and intermediate support sheet 16 isobtained with the aid of at least one projecting part 22, which isarranged on either one of the two elements, for example on support sheet18, and is disposed in a hollow cutout of an approximately cooperatingshape at the level of the other element, for example stopper 20. Theprojecting part has anti-stripping shapes 24, as well as at least oneplastic deformation 26 near said projecting part 22 so as to create aslight expansion, ensuring the connection between the two elements bywedging.

An anti-stripping shape means that the projecting part is provided witha reduced cross-section at its foot (zone of junction with the elementthat supports it).

As can be seen from FIGS. 6A to 6C, the wedging stresses arise onlylocally during plastic deformation and do not create excessivedeformations of the sheet and/or the stopper.

In FIGS. 1 and 2, the projecting part or parts 22 are provided at alevel portion of the intermediate sheet 18.

FIG. 3 illustrates an embodiment in which the projecting part or parts22 are provided at a level portion of the stopper 20.

Depending on the case, the projecting part 22 is in the form of a notchwith rounded edges, or it comprises a circumference with a succession ofsegments. FIGS. 6A and 6B illustrate the different embodiments in anon-exhaustive manner.

Preferably, plastic deformation 26, which can be seen in FIGS. 5A and5B, is obtained by punching at the level of the projecting part. Thepunching is in the form of points, or in linear or level form.

According to another embodiment, the connection comprises at least twoprojecting parts 22, 22′ that are arranged on a first element, namely oneither support sheet 18 or stopper 20, or preferably on an intermediatepart 28 of the second element. The stopper 20 or support sheet 18,disposed between the two parts, undergoes a plastic deformation so as tocreate a radial expansion that ensures the connection of the twoelements by wedging. Depending on the case, the two projecting parts 22and 22′, or only the intermediate parts 28, comprise anti-strippingshapes.

In a different variant, the plastic deformation or deformations 26 areproduced at the level of the projecting parts.

In the case where there is a multiplicity of projecting parts 22, atleast one plastic deformation and preferably several of them can beprovided on either the projecting parts 22 and/or the intermediate parts28.

FIG. 4 illustrates a preferred embodiment in which the projecting partor parts have particular shapes.

In this case, the projecting part or parts 22 have an elongated shapewith a connection in the form of a narrow strip. This shape makes itpossible to increase the contact surface between stopper 20 and supportsheet 18 and, by plastic deformation, to obtain a more resistantconnection.

Regardless of the shape of the projecting parts 22, the parts arepreferably spaced regularly, and the intermediate parts 28 have aprofile that is approximately identical to that of projecting parts 22.

It will be understood that the invention is obviously not limited to theembodiments represented and described hereinabove, but that, on thecontrary, it covers all variants particularly in regard to the materialsused, the shapes of the active part of the stopper and the number ofexternal sheets.

Moreover, the different sheets 12, 18 and the stopper 20 can eachconsist of a single sheet or of a stack of sheets.

Moreover, the means of connection between the stopper and the supportsheet can apply to a single stopper as well as, in the case of amulticylinder gasket, to a group of stoppers connected to each other bya narrow strip.

Finally, the zone of contact between the stopper and the intermediatesupport sheet can comprise an orifice for the passage of fluid, forexample water or oil.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A cylinder head gasket with at least one opening corresponding to acombustion chamber, comprising: at least one external sheet including acircular rib that surrounds the opening and is disposed at a distancefrom said opening; a support sheet disposed against the face of theexternal sheets that includes the circular rib, the support sheetincluding another opening with a diameter greater than the opening ofthe external sheet so as to define a space; and a stopper disposed inthe space in the form of an annular lining, the stopper having aninternal diameter that corresponds to that of the opening and anexternal diameter that is adjusted to the opening of the support sheetso as to be disposed from edge to edge; wherein a connection between thestopper and the support sheet contains at least one projecting part thatis arranged on either the stopper or the support sheet, the projectingpart being disposed in a hollow cutout in the form of a cooperatingshape that is formed in either the stopper or the support sheet; and theprojecting part of having anti-stripping shapes and at least one plasticdeformation near the projecting part so as to create a slight expansionthat ensures the connection between the stopper and the support sheet bywedging.
 2. The cylinder head gasket according to claim 1, wherein theplastic deformation is created at the projecting part.
 3. The cylinderhead gasket according to claim 1, wherein the connection between thestopper and the support sheet contains at least two projecting partsarranged on a first element as well as a plastic deformation at anintermediate part of a second element and disposed between the twoprojecting parts so as to generate a radial expansion ensuring theconnection between the two elements by wedging.
 4. The cylinder headgasket according to claim 3, wherein the plastic deformation ordeformations are also provided at the level of the projecting part orparts.
 5. The cylinder head gasket according to claim 1, wherein theplastic deformation or deformations are obtained by punching.
 6. Thecylinder head gasket according to claim 1, wherein the projecting partsare spaced regularly.
 7. The cylinder head gasket according to claim 6,wherein the intermediate parts have a profile that is approximatelyidentical to that of the projecting parts.
 8. The cylinder head gasketaccording to claim 1, wherein the projecting part or parts have anelongated shape, the cross-section at a foot of the projecting partbeing thinner than at the end thereof.